The man appointed as the new managing director of Renault's Formula 1 program has left the French car company before the 2019 season gets underway.Thierry Koskas was named president of Renault ...

Green said testing the 2019 technical rule changes was an eye-opening experience.

"The car looked really bad when we first put it in the wind tunnel," he said. "The performance loss was huge. We are talking about several seconds in lap time."

Green said it will therefore be a very busy year for the engineers who are involved in developing the cars.

"The learning curve is very steep for everyone," he said. "I expect a long fight. Once the new season gets going, engineers will definitely be keen to see what solutions the competition comes up with."

As for whether the rules really will make overtaking easier in 2019, Green answered: "That's not easy to say. But I'm already worried about it."